Solar wind fence for an array of trackers

ABSTRACT

A solar tracker array has solar modules that may be configured to operate as a wind fence according to a wind characteristic.

CROSS REFERENCE TO RELATED APPLICATION

The present disclosure claims priority to U.S. patent application Ser.No. 14/9622,087 filed Oct. 23, 2015, now U.S. Pat. No. 10,601,364, whichclaims the benefit of U.S. Provisional Application No. 62/068,323, filedon Oct. 24, 2014, which is incorporated by reference herein in itsentirety.

BACKGROUND

The present application relates generally to a tracking system for solarpanels. More specifically, embodiments provide tracking systems that aresuitable for solar panels. In a specific embodiment, a tracking systemis fully adjustable at each of the pillars, a plurality of trackingsystems working in conjunction with each other to protect the system asa whole, among other aspects. There are other embodiments as well.

As the population of the world increases, industrial expansion has ledto an equally large consumption of energy. Energy often comes fromfossil fuels (including coal and oil), hydroelectric plants, nuclearsources, and others. As an example, the International Energy Agencyprojects further increases in oil consumption, with developing nationssuch as China and India accounting for most of the increase. Almostevery element of our daily lives depends, in part, on oil, which isbecoming increasingly scarce. As time further progresses, an era of“cheap” and plentiful oil is coming to an end. Accordingly, alternativesources of energy have been developed.

Along oil, people have also relied upon other sources of energy such ashydroelectric, nuclear, and the like to provide our electricity needs.For example, most of the conventional electricity required for home andbusiness use come from coal- or natural gas-fired turbines, nuclearpower generation plants, and hydroelectric plants, as well as otherforms of renewable energy. Home and business use of electrical power hasbeen stable and widespread.

Much of the useful energy found on the Earth comes from our sun.Generally all common plant life on the Earth achieves life usingphotosynthesis processes from sun light. Fossil fuels such as oil werealso developed from biological materials derived from energy associatedwith the sun. For human beings, sunlight has been essential. For life onthe planet Earth, the sun has been the most important energy source andfuel for modern day solar energy.

Solar energy possesses many desirable characteristics. Solar energy isrenewable, clean, abundant, and often widespread. Certain technologieshave been developed to capture solar energy, concentrate it, store it,and convert it into other useful forms of energy.

Solar panels have been developed to convert sunlight into energy. As anexample, solar thermal panels often convert electromagnetic radiationfrom the sun into thermal energy for heating homes, running certainindustrial processes, or driving high grade turbines to generateelectricity. As another example, solar photovoltaic panels convertsunlight directly into electricity for a variety of applications.

Solar panels are generally composed of an array of solar cells, whichare interconnected to each other. The cells are often arranged in seriesand/or parallel groups of cells in series. Accordingly, solar panelshave great potential to benefit our nation, security, and human users.They can even diversify our energy requirements and reduce the world'sdependence on oil and other potentially detrimental sources of energy.

Although solar panels have been used successfully for certainapplications, there are still limitations. Often, solar panels areunable to convert energy at their full potential due to the fact thatthe sun is often at an angle that is not optimum for the solar cells toreceive solar energy. In the past, various types of conventional solartracking mechanisms have been developed to address this issue.Unfortunately, conventional solar tracking techniques are ofteninadequate. These and other limitations are described throughout thepresent specification, and may be described in more detail below.

From the above, it is seen that techniques for improving solar systemsare highly desirable.

SUMMARY

In an example, the present invention provides a solar tracker apparatus.The apparatus has a torque tube; and a plurality of solar modulesconfigured spatially along the torque tube and configured as a windshield for an interior zone comprising a plurality of tracker apparatus.In an example, the plurality of solar modules are configured to change adirection of on-coming wind to move substantially over a plurality ofsolar modules configured on the plurality of tracker apparatus in theinterior zone. In an example, each of the plurality of solar modules inthe interior region is configured in a substantially normal directionwith respect to a direction of gravity.

In an example, the apparatus is provided within an exterior zone of anarray of solar tracker apparatus; wherein the plurality of solar modulesconfigured to change the direction is configured as a wind fence, andconfigured in an offensive position to divert the on-coming wind, whilethe plurality of solar modules in the interior region are configured ina defensive position and each of the solar panels are protected from theplurality of solar modules provided on the exterior zone.

In an example, the apparatus is provided within an exterior zone andeach of the plurality of solar modules is configured to act as a windfence for an interior zone of an array of solar tracker apparatus.

In an example, the present invention provides a solar system comprisingan array of solar modules. The system has an interior zone comprising afirst plurality of tracker apparatus, each of which is configured with afirst plurality of solar modules; and an exterior zone comprising atleast one tracker apparatus configured with a torque tube configuredwithin a frame structure having a first interior stop region and asecond interior stop region. In an example, the torque tube is capableof moving about an arc from a first angle to a second angle. In anexample, a plurality of solar modules are disposed with the framestructure are configured as a windshield.

In an example, the present invention provides a method of operating asolar array system. In an example, the method includes providing anarray of solar modules. In an example, the array of solar modulescomprises an interior zone comprising a first plurality of trackerapparatus, each of which is configured with a first plurality of solarmodules, and an exterior zone comprising at least one tracker apparatusconfigured with a torque tube configured within a frame structure havinga first interior stop region and a second interior stop region. In anexample, the torque tube is capable of moving about an arc from a firstangle to a second angle. In an example, the method includes detecting apredetermined wind characteristics during a time frame, the windcharacteristic being in one of a plurality of ranges. In an example, theplurality of ranges including at least a first range, a second range,and a third range. In an example, the method includes configuring theone tracker apparatus in a normal state when the wind characteristic inthe first range; configuring the one tracker apparatus in a defensivestate configured to allow each of the first plurality of trackerapparatus to be operable in a normal manner to rotate each of the solarmodules in a range from about −60 Degrees to +60 Degrees when the windcharacteristic in the second range. The method includes configuring theone tracker apparatus in a defensive state and each of the plurality offirst plurality of tracker apparatus in a locked at 0 Degrees state whenthe wind characteristic in the third range.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified diagram illustrating a solar tracker configuredin different angles according to an embodiment.

FIG. 2 shows a solar array system including a plurality of solartrackers in a normal operating mode according to an embodiment.

FIG. 3 shows a configuration of the solar array system in a partialdefense mode having outer solar trackers configured as a wind fenceaccording to an embodiment.

FIG. 4 shows a configuration of the solar array system in a full defensemode having outer solar trackers configured as a solar wind fenceaccording to an embodiment.

FIG. 5 is a side view of the configuration shown in FIG. 4 according toan embodiment.

FIG. 6 illustrates a process of operating a solar array system accordingto an embodiment.

DETAILED DESCRIPTION

In conventional tracker designs, wind forces may lead to uncontrollablemovement of the solar modules on the tracker leading to an increase inresonance and movement until supporting or positioning components, suchas a torque tube or a slew gear, breaks. Once a row of trackers isinfluenced by such wind forces, other trackers that may be adjacent tothe that row are influenced and may participate in the uncontrollablemovement.

FIG. 1 is a simplified diagram illustrating a solar tracker 100configured in different angles according to an illustrative embodiment.The solar tracker 100 has a torque tube 102 and a plurality of solarmodules 104 configured spatially along the torque tube 102.

When the solar tracker 100 is configured in a first angle, the torquetube 102 and the plurality of solar modules 104 are respectivelydisposed as indicated by reference character 102 and 104. When the solartracker 100 is configured in a second (horizontal) angle, the torquetube 102 and the plurality of solar modules 104 are respectivelydisposed as indicated by reference character 102′ and 104′. When thesolar tracker 100 is configured in a third angle, the torque tube 102and the plurality of solar modules 104 are respectively disposed asindicated by reference character 102″ and 104″.

FIG. 1 shows the first, second, and third angles in which the solartracker 100 may be configured, but embodiments are not limited thereto.In an embodiment, the torque tube 102 is capable of moving about an arcfrom the first angle to the third angle.

FIG. 2 shows a solar array system (also known as a solar system) 200including first to eighth solar trackers 100-1 to 100-8 in a normaloperating mode according to an embodiment. The solar array system 200includes an interior zone 202 and first and second exterior zones 204Aand 204B.

The first solar tracker 100-1 is disposed in the first exterior zone204A. The second to seventh solar trackers 100-2 to 100-7 are disposedin the interior zone 202. The eighth solar tracker 100-8 is disposed inthe second exterior zone 204B.

The first and eighth solar trackers 100-1 and 100-8 disposed in thefirst and second exterior zones 204A and 204B, respectively, areoperable to act as wind fences for the second to seventh solar trackers100-2 to 100-7 disposed in the interior zone 202, as shown in FIGS. 3through 5.

In an embodiment, one or more of the first and eighth solar trackers100-1 and 100-8 disposed in the first and second exterior zones 204A and204B includes a torque tube configured within a frame structure having afirst interior stop region and a second interior stop region. The firstinterior stop region and a second interior stop region may correspond toa first angle and a second angle, respectively, and the one or more ofthe solar trackers 100-1 and 100-8 may be configured to move the torquetube about an arc from the first angle to the second angle.

In the normal operating mode, the first to eighth solar trackers 100-1to 100-8 may each be configured at angles that optimize collection ofsolar energy by the solar array system 200. A person of ordinary skillin the art would understand how to determine the angles that optimizecollection of solar energy.

The solar array system 200 may operate in the normal operating mode whena wind characteristic is in a first range. In an embodiment, the firstrange may include a wind velocity in a direction orthogonal to a longaxis of torque tubes of the first to eighth solar tracker 100-1 to 100-8being below a first threshold value.

FIG. 3 shows the solar array system 200 in a partial defense modewherein outer solar trackers, that is, the first and eighth solartrackers 100-1 and 100-8 disposed in the first and second exterior zones204A and 204B, respectively, are each configured as a wind fence,according to an embodiment. The solar array system 200 may operate inthe partial defense mode when a wind characteristic is in a secondrange. The second range may include a wind velocity greater than thefirst threshold value and less than a second threshold value.

The first and eighth solar trackers 100-1 and 100-8 disposed in thefirst and second exterior zones 204A and 204B act as a wind fence forthe second to seventh solar trackers 100-2 to 100-7 disposed in theinterior zone 202 when in the partial defense mode. The second toseventh solar trackers 100-2 to 100-7 operate as in the normal operatingmode when in the partial defense mode.

The first and eighth solar trackers 100-1 and 100-8 may be configured asa wind fence by configuring the first and eighth solar trackers 100-1and 100-8 to have an angle according to one of a first interior stopregion and a second interior stop region of the respective torque tubeswhen in the partial defense mode. When a solar tracker is configured asa wind fence, the solar modules of the solar tracker are configured tofunction as a wind shield.

In an embodiment, only one of the first and eighth solar trackers 100-1and 100-8 may be configured as a wind fence when in the partial defensemode, and the other of the first and eighth solar trackers 100-1 and100-8 may operate as in the normal operating mode when in the partialdefense mode. For example, in an embodiment, only the one of the firstand eighth solar trackers 100-1 and 100-8 that is upwind of the interiorzone 202 is configured as a wind fence in the partial defense mode.

FIG. 4 shows a perspective view of the solar array system 200 in a fulldefense mode according to an embodiment. FIG. 5 is a side view of thesolar array system 200 in the full defense mode of FIG. 4.

The solar array system 200 may operate in the full defense mode when awind characteristic is in a third range. The third range may include awind velocity greater than the second threshold value.

One or more of the first and eighth solar trackers 100-1 and 100-8 maybe configured as a wind fence when in the full defense mode, asdescribed for FIG. 3. The second to seventh solar trackers 100-2 to100-7 are locked at a 0 degree angle (that is, are locked in asubstantially horizontal position) when in the full defense mode.

In an embodiment, only one of the first and eighth solar trackers 100-1and 100-8 may be configured as a wind fence when in the full defensemode, and the other of the first and eighth solar trackers 100-1 and100-8 may locked at the 0 degree angle. For example, in an embodiment,only the one of the first and eighth solar trackers 100-1 and 100-8 thatis upwind of the interior zone 202 is configured as a wind fence in thefull defense mode.

FIG. 6 illustrates a process 600 of operating a solar array systemaccording to an embodiment. In an example, the solar array systemincludes an interior zone comprising a plurality of interior trackerapparatus, and at least one exterior zone including at least oneexterior tracker apparatus. Each of the interior and exterior trackerapparatus includes a plurality of solar modules.

In an embodiment, one or more of the interior or exterior trackerapparatus is operable to rotate their respective the solar modules in arange from −60 Degrees to +60 Degrees, wherein 0 degrees corresponds toa horizontal disposition of the solar modules. In an embodiment, each ofthe interior tracker apparatus is operable to lock their respectivesolar modules at 0 Degrees.

At S602, the process 600 determines a predetermined wind characteristicduring a time frame, the wind characteristic being in one of a pluralityof ranges. In an embodiment, the plurality of ranges includes at least afirst range, a second range, and a third range.

At S604, the process 600 determines whether the wind characteristic isin the first range. The process 600 proceeds to S606 when the windcharacteristic is determined to be in the first range, and proceeds toS608 otherwise.

At S606, the process 600 configures the one or more exterior trackerapparatus in a normal state when the wind characteristic is in the firstrange. The normal state may be a sun-tracking configuration adapted tocollect solar energy. The process 600 then proceeds to S612.

At S608, the process 600 determines whether the wind characteristic isin the second range. The process 600 proceeds to S610 when the windcharacteristic is determined to be in the second range, and proceeds toS614 otherwise.

At S610, the process 600 configures the one or more exterior trackerapparatus in a defensive state when the wind characteristic is in thesecond range. The defensive state may be a wind fence state. The windfence state may include disposing the solar modules of the exteriortracker apparatus at either 60 or −60 degrees. The process 600 thenproceeds to S612.

At S612, the process 600 configures the plurality of interior trackerapparatus in a normal state when the wind characteristic is in the firstor second range. The process 600 then returns to S602.

At S614, the process 600 configures the one or more exterior trackerapparatus in the defensive state, such as described above with respectto S610, when the wind characteristic is not in the first or secondrange, that is, when the wind characteristic is in the third range. Inan example, the defensive state can be configured in a locked flatposition or normal position with respective gravity, while the outermodules are in an offensive state to divert wind away from the innerregion of the array of solar panels. Of course, the term “offensive” and“defensive” are used in its literal meaning, and should be interpretedusing ordinary meaning, and may be used interchangeably.

At S616, the process 600 configures the plurality of interior trackerapparatus in a locked 0 degree state when the wind characteristic is inthe third range. In the locked 0 degree state, the solar modules of theplurality of interior tracker apparatus may be substantially parallel tothe ground. The process 600 then returns to S602.

The process 600 may be carried out using a controller of the solar arraysystem. In an embodiment, the controller performs the process 600 usinga processor or controller executing computer programming instructionsstored in a non-transitory computer-readable media. In an embodiment,the controller performs the process 600 using custom logic circuitsembodying operations of the process 600.

In an example, the present invention provides a solar tracker system.The solar tracker system has a first pillar structure and a secondpillar structure. In an example, the system has a torque tube configuredbetween the first pillar structure and the second pillar structure and aplurality of solar modules configured spatially along the torque tubefrom a first end to a second end.

In an example, the system has a panel rail configured to each of theplurality of solar modules. That is, the system has a plurality of panelrail devices coupling respective plurality of solar modules.

In an example, the system has a clamp device coupled to sandwich thetorque tube between a lower portion of the clamp device and each panelrail. In an example, the clamp device is a U-bolt that has a lowerregion coupled to the lower region of the torque tube, and each of thebolt structures is inserted into an opening in the panel rail. The panelrail is disposed underlying a pair of solar modules and is configured tohold the pair of solar modules, while being clamped onto the torque tubeusing the U-bolt and a pair of bolts securing the panel rail to thetorque tube.

In an example, the system has a mechanical isolator comprising anelastic material configured to separate the panel rail from the torquetube cause destructive interference with a natural resonant frequency ofthe system without the mechanical isolator to reduce a mechanicalvibration of the system. In an example, the elastic material comprises arubber or a polymer that has sufficient rigidity. In an example, thematerial can also be configured with one or more openings to furtherallow the thickness of material to flex and/or absorb vibration. Furtherdetails of the system can be found in U.S. Ser. No. 14/734,981, commonlyassigned, and hereby incorporated by reference herein in its entirety.The '981 application is assigned to NEXTRACKER INC., 6200 PASEO PADREPARKWAY, FREMONT, CALIFORNIA 94555, and titled MASS DAMPER FOR SOLARTRACKER.

In a specific embodiment, the present invention provides a trackerapparatus for solar modules. The tracker apparatus has a first piercomprising a first pivot device and a second pier comprising a drivemount. The drive mount is capable for construction tolerances in atleast three-axis and is configured to a drive device. The drive devicehas an off-set clamp device coupled to a cylindrical bearing devicecoupled to a clamp member. The apparatus has a cylindrical torque tubeoperably disposed on the first pier and the second pier. The cylindricaltorque tube comprises a first end and a second end, and a notch. Thenotch is one of a plurality of notches spatially disposed along a lengthof the cylindrical torque tube. The apparatus has a clamp configuredaround an annular portion of the cylindrical torque tube and mate withthe notch to prevent movement of the clamp. The clamp comprises asupport region configured to support a portion of a solar module.

In an alternative embodiment, the present invention provides analternative solar tracker apparatus. The apparatus has a drive device, acrank coupled to the drive device and configured in an offset manner toa frame assembly. The frame assembly is coupled to a plurality of solarmodules.

In an example, the apparatus has a continuous torque tube spatiallydisposed from a first region to a second region. The crank comprises afirst crank coupled to a first side of the drive device and a secondcrank coupled to a second side of the drive device. The crank comprisesa first crank coupled to a first side of the drive device and a secondcrank coupled to a second side of the drive device; and furthercomprises a first torque tube coupled to the first crank and a secondtorque tube coupled to the second crank. The crank comprises a firstcrank coupled to a first side of the drive device and a second crankcoupled to a second side of the drive device; and further comprises afirst torque tube coupled to the first crank and a second torque tubecoupled to the second crank, and further comprises a first swage fittingcoupling the first crank to the first torque tube and a second swagefitting coupling the second crank to the second torque tube. Theapparatus also has a pier coupled to the drive device. In an example,the apparatus also has a drive mount coupled to a pier.

In an alternative embodiment, the present invention provides analternative solar tracker apparatus. The apparatus has a center of masswith an adjustable hanger assembly configured with a clam shell clampassembly on the adjustable hanger assembly and a cylindrical torque tubecomprising a plurality of torque tubes configured together in acontinuous length from a first end to a second end such that the centerof mass is aligned with a center of rotation of the cylindrical torquetubes to reduce a load of a drive motor operably coupled to thecylindrical torque tube.

In an example, the drive motor is operable to move the torque tube aboutthe center of rotation and is substantially free from a load. The centerof rotation is offset from a center of the cylindrical torque tube.

In an alternative embodiment, the present invention provides a solartracker apparatus. The apparatus has a clamp housing member configuredin a upright direction. The clamp housing member comprises a lowerregion and an upper region. The lower region is coupled to a pierstructure, and the upper region comprises a spherical bearing device.The upright direction is away from a direction of gravity. The apparatushas a clam shell clamp member coupled to the cylindrical bearing and atorque tube coupled to the spherical bearing to support the torque tubefrom the upper region of the clamp housing member. The torque tube isconfigured from an off-set position from a center region of rotation.

In an example, the apparatus is configured substantially free from anywelds during assembly. Reduced welding lowers cost, improvesinstallation time, avoids errors in installation, improvesmanufacturability, and reduces component count through standardizedparts. The torque tube is coupled to another torque tube via a swagedevice within a vicinity of the clam shall clamp member. In an example,the connection is low cost, and provides for strong axial and torsionalloading. The apparatus is quick to install with the pokey-yoke design.The torque tube is coupled to an elastomeric damper in line to dampentorque movement to be substantially free from formation of a harmonicwaveform along any portion of a plurality of solar panels configured tothe torque tube. The apparatus also has a locking damper or rigidstructure to configure a solar panel coupled to the torque tube in afixed tilt position to prevent damage to stopper and lock into afoundation-in a position that is substantially free from fluttering inan environment with high movement of air. The apparatus furthercomprises a controller apparatus configured in an inserter box providedin an underground region to protect the controller apparatus. Theapparatus has a drive device to linearly actuate the torque tube. In anexample, the apparatus uses an electrical connection coupled to a drivedevice. In an example, the spherical bearing allows for a constructiontolerance, tracker movement, and acts as a bonding path of leastresistance taking an electrical current to ground. The apparatus can beone of a plurality of tracker apparatus configured in an array within ageographic region. Each of the plurality of tracker apparatus is drivenindependently of each other to cause each row to stow independently at adifferent or similar angle.

Still further, the present invention provides a tracker apparatuscomprising a clam shell apparatus, which has a first member operablycoupled to a second member to hold a torque tube in place.

In an example, the apparatus also has a clamp housing operably coupledto the clam shell apparatus via a spherical bearing device such that thespherical bearing comprises an axis of rotation. The axis of rotation isdifferent from a center of the torque tube. The apparatus furthercomprises a solar module coupled to the torque tube.

In an example, the invention provides a tracker apparatus comprising aplurality of torque tubes comprising a first torque tube coupled to asecond torque tube coupled to an Nth torque tube, whereupon N is aninteger greater than 2. Each pair of torque tubes is coupled to eachother free from any welds.

In an example, each pair of torque tubes is swaged fitted together. Eachof the torque tubes is cylindrical in shape. Each of the plurality oftorque tubes is characterized by a length greater than 80 meters. Eachof the torque tubes comprises a plurality of notches. In an example, theapparatus also has a plurality of U-bolt devices coupled respectively tothe plurality of notches. Each of the plurality of torque tubes are madeof steel.

In an alternative embodiment, the present invention provides a trackerapparatus having a pier member comprising a lower region and an upperregion. A clamp holding member is configured to the upper region and iscapable of moving in at least a first direction, a second directionopposite to the first direction, a third direction normal to the firstdirection and the second direction, a fourth direction opposite of thethird direction, a fifth direction normal to the first direction, thesecond direction, the third direction, and the fourth direction, and asixth direction opposite of the fifth direction.

In yet an alternative embodiment, the present invention provides a solartracker apparatus. The apparatus has a clamp housing member configuredin a upright direction. The clamp housing member comprises a lowerregion and an upper region. The lower region is coupled to a pierstructure. The upper region comprises a spherical bearing device. Theupright direction is away from a direction of gravity. The apparatus hasa clam shell clamp member coupled to the cylindrical bearing and theclam shell clamp being suspended from the cylindrical bearing. In anexample, the apparatus has a torque tube comprising a first end and asecond end. The first end is coupled to the spherical bearing to supportthe torque tube from the upper region of the clamp housing member. Thetorque tube is configured from an off-set position from a center regionof rotation. The apparatus has a drive device coupled to the second endsuch that the drive device and the torque tube are configured to besubstantially free from a twisting action while under a load, e.g.,rotation, wind, other internal or external forces.

In an example, the present invention provides a solar tracker apparatuscomprising a clamp assembly, the clamp assembly comprising a housinghaving an opening having a major plane normal to a length of acontinuous torque tube, the opening comprising a first inner region anda second inner region, the first inner region acts as a first stop forthe continuous torque tube when moved in a first radial direction untilcontact with the first inner region, and the second inner region acts asa second stop for the continuous torque tube when moved in a secondradial direction until contact with the second inner region, the housinghaving a pivotable hanger assembly configured to suspend the continuoustorque tube such that the continuous torque tube traverse through themajor plane. In an example, the apparatus comprises a center of masswith the pivotable hanger assembly the continuous torque tube comprisinga plurality of cylindrical torque tubes configured together in acontinuous length from a first end to a second end such that the centerof mass is aligned with a center of rotation of the cylindrical torquetubes to reduce a load of a drive motor operably coupled to thecylindrical torque tube. Further details can be found in U.S. Ser. No.14/184,656 filed Feb. 19, 2014, and titled BALANCED SOLAR TRACKER CLAMP,commonly assigned, and hereby incorporated by reference herein in itsentirety.

It is understood that the examples and embodiments described herein arefor illustrative purposes only and that various modifications or changesin light thereof will be suggested to persons skilled in the art and areto be included within the spirit and purview of this application andscope of the appended claims.

What is claimed is:
 1. A solar tracker apparatus comprising: a torquetube; and a plurality of solar modules configured spatially along thetorque tube, and configured as a wind shield for an interior zonecomprising a plurality of tracker apparatus, the plurality of solarmodules are configured to change a direction of on-coming wind to movesubstantially over a plurality of solar modules configured on theplurality of tracker apparatus in the interior zone, each of theplurality of solar modules in the interior region configured in asubstantially normal direction with respect to a direction of gravity.